You can copy your notes vault and test on the copy, or make a miniature test vault and do it there.
Or you could restore from your backups. If you don’t have backups of all of the computer files you care about, I recommend changing that before doing anything else. Obsidian’s help has a page about it, and most of it applies to non-Obsidian files too.
Actually find and replace is tricky for tags in properties.
Tags in properties appear like this in the raw text:
---
tags:
- mytag
---
while tags in the actual body of the document appear as #mytag.
So a find and replace for #mytag would not affect properties, right?
Edit: A few more caveats that might thwart find-and-replace are discussed in GitHub - pjeby/tag-wrangler: Rename, merge, toggle, and search tags from the Obsidian tag pane.
Right.
This feature would be a lifesaver for managing my notes! I often have to rename or delete tags across several files, and doing it one by one is such a drag. If I could do this in bulk, it would really streamline my process and help me stay organized without all the repetitive work! And Tag Wrangler should be core.
Renaming, merging, deleting, and organizing tags is such an essential feature for a note-taking app with tags support. It’s shocking to learn that an advanced app like Obsidian can’t handle tag management 
The fastest and easiest way to delete/rename tags I’ve found is installing the Replace All plugin
No need for VScode or any external program, just click or write the tag you want to modify, write the desired outcome (you can just add a space or anything to delete the tag) and push enter. All the instances of that tag across your vault will be deleted or renamed.
Concrete +1
Earlier “Tag Wrangler” worked fine for renaming tags but since the new bases have been added it’s not sufficient anymore. It doesn’t rename the tags used in base views.
Example: Using the tag #Idea as a filter in a base view and then renaming it to #Invention will just update the #Idea to #Invention inside the notes (files), but not in the base views which have used it as a filter. You have to manually rename the filter #Idea in every base view to #Invention.
I just can’t trust using tags for base view filters. The semantics/meaning of a tag may change over time and I have to be able to mark this by giving it a more precise (e.g. more concrete/abstract) name.
Similar (Overview): Wrangling Properties — Renaming List Property Options — Dynamic Base Filters